Conventional revolvers have a frame, a barrel secured to the forward end of the frame, a cylinder rotatably mounted on the frame, the cylinder being formed with a plurality of chambers each of which is adapted to receive a cartridge and each moving successively into alignment with the barrel when the cylinder is rotated, a hammer pivotably mounted on the frame in a position to strike a cartridge contained in the uppermost chamber of the cylinder, a trigger pivotably mounted below the cylinder for rotation from its at-rest position to its ready-to-fire position when the hammer is cocked, a cylinder pawl for rotating the cylinder when the hammer is cocked or when the trigger is pulled, and a cylinder latch for preventing rotation of the cylinder when the revolver is fired. The outer surface of the cylinder is formed with a plurality of cylinder latch notches each corresponding to one of the cartridge receiving chambers of the cylinder, and the cylinder latch has a nose portion that is adapted to releasably engage each of the cylinder latch notches of the cylinder in succession (usually, the lowermost cylinder notch) as the cylinder is rotated. The nose of the cylinder latch engages the lowermost of the cylinder latch notches of the cylinder to maintain the uppermost chamber of the cylinder in alignment with the barrel of the revolver when the firing mechanism of the revolver is in its ready-to-fire condition and is withdrawn from engagement with said notch when the cylinder is rotated to bring the next chamber into alignment with the barrel of the revolver.
It is important that the nose of the cylinder latch firmly engage the lowermost of the cylinder notches of the cylinder to prevent rotation of the cylinder when the firing mechanism of the revolver is in its ready-to-fire condition. Moreover, after the revolver has been fired and the hammer and trigger have returned to their respective at-rest positions, it is equally important that the cylinder be free to rotate to bring the next chamber thereof into alignment with the barrel when the revolver is being cocked in preparation for the next shot. Accordingly, as previously noted the cylinder latch first must be moved to withdraw the nose portion thereof from engagement with the lowermost of the cylinder latch notches and then must be released to permit the nose portion to engage the next cylinder latch notch when the next chamber of the cylinder moves into alignment with the barrel. More specifically, when the hammer and the trigger are rotated from their at-rest to their ready-to-fire positions, the nose of the cylinder latch is withdrawn temporarily from engagement with the lowermost of the cylinder latch notches of the cylinder, the cylinder pawl is moved upwardly to engage the indexing ratchets of the cylinder and thereby commence rotation of the cylinder, and then the cylinder latch is released to allow the nose thereof to contact and slide along the outer surface of the rotating cylinder, the nose of the cylinder latch slipping into and engaging the next (and now the lowermost) cylinder latch notch when the uppermost chamber corresponding thereto moves into alignment with the barrel of the revolver. The movement of the hammer, trigger, cylinder pawl, cylinder latch, and cylinder must be carefully coordinated to achieve the desired disengagement and reengagement of the cylinder and cylinder latch without allowing the cylinder to become misaligned with the barrel at the moment the revolver is fired. A number of cylinder latch mechanisms have heretofore been devised to successfully accomplish this result among which are those disclosed in U.S. Pat. Nos. 3,654,720, 3,768,190, and 3,777,384 to Ruger et al.
U.S. Pat. No. 3,654,720 discloses an advantageous trigger guard assembly for a revolver wherein the trigger and cylinder pawl (as well as certain other parts of the firing mechanism) are mounted on the trigger guard which, in turn, is removably mounted on the underside of the frame of the revolver. This construction greatly simplifies the assembly and disassembly of the revolver and also greatly strengthens the frame of the revolver by eliminating the need for a separate side plate that must be removed when a revolver of conventional construction is disassembled for cleaning or repair. The cylinder latch of this revolver is a separate part that is not actually secured to any other part, the cylinder latch being maintained in its operational position by the adjacent parts of the firing mechanism and frame when the revolver is properly assembled. This can lead to some inconvenience if the separate cylinder latch is mislaid during disassembly or is incorrectly positioned when the revolver is reassembled.
We have now devised an improvement in the cylinder latch mechanism of revolvers that eliminates the possibility of loss of the cylinder latch or misassembly of the mechanism itself by securely mounting the pivoted cylinder latch on the frame or on the trigger guard of the revolver. The mechanism is rugged and reliable and is provided with a cylinder latch actuator that is automatically locked in its cylinder latch actuator position when the revolver is being cocked, thereby further reducing the possibility of malfunctioning of the mechanism. Other important advantages of the cylinder latch mechanism will become apparent from the ensuing detailed description thereof.